Why is ovarian cancer difficult to detect in the early stages?

Early stage epithelial ovarian cancer is extremely difficult to detect, as evidenced by the fact that the majority of women continue to be diagnosed with advanced stage disease. This is partly due to the fact that each ovary is a small (2 cm x 3 cm), oval-shaped organ embedded deep within the abdominal cavity on each side of the uterus. In addition, the signs and symptoms are generally non-specific and may include:

• Gastrointestinal upset, such as gas, indigestion or nausea
• Pelvic and/or abdominal pain or discomfort
• Pelvic and/or abdominal bloating or swelling
• A constant feeling of fullness
• Unexplained change in bowel and/or bladder habits
• fatigue
• Unexplained weight loss or gain
• Abnormal or postmenopausal bleeding

Because these potential symptoms and signs of ovarian cancer are vague, only about 25% of ovarian cancers are found in the early stages. Symptoms typically become more prominent in advanced stages when tumor growth creates pressure on the bladder and rectum, and ascites (fluid in the abdomen causing abdominal distension) begins to form.